elfcopy: fix symbol table handling when sections come after symtab/strtab

  Fix a symbol table handling bug in elfcopy: elfcopy puts .symtab,
  .strtab and .shstrtab sections in the end of the output object.  If
  the input objects have more sections after any of these 3 sections,
  the section table will be reordered, and in that case the section
  symbols should be regenerated for relocations.

  The bug is triggered since newer clang puts .strtab section in the
  beginning of the object produced.

   Ticket: #525

Reported by:	royger
Obtained from:	ELF Tool Chain r3443

1 files changed, 15 insertions, 2 deletions

diff --git a/contrib/elftoolchain/elfcopy/sections.c b/contrib/elftoolchain/elfcopy/sections.c
index 5848eab..1434138 100644
--- a/contrib/elftoolchain/elfcopy/sections.c
+++ b/contrib/elftoolchain/elfcopy/sections.c
@@ -343,7 +343,7 @@ create_scn(struct elfcopy *ecp)
 	GElf_Shdr	 ish;
 	size_t		 indx;
 	uint64_t	 oldndx, newndx;
-	int		 elferr, sec_flags;
+	int		 elferr, sec_flags, reorder;
 
 	/*
 	 * Insert a pseudo section that contains the ELF header
@@ -367,6 +367,7 @@ create_scn(struct elfcopy *ecp)
 		errx(EXIT_FAILURE, "elf_getshstrndx failed: %s",
 		    elf_errmsg(-1));
 
+	reorder = 0;
 	is = NULL;
 	while ((is = elf_nextscn(ecp->ein, is)) != NULL) {
 		if (gelf_getshdr(is, &ish) == NULL)
@@ -482,8 +483,20 @@ create_scn(struct elfcopy *ecp)
 		/* create section header based on input object. */
 		if (strcmp(name, ".symtab") != 0 &&
 		    strcmp(name, ".strtab") != 0 &&
-		    strcmp(name, ".shstrtab") != 0)
+		    strcmp(name, ".shstrtab") != 0) {
 			copy_shdr(ecp, s, NULL, 0, sec_flags);
+			/*
+			 * elfcopy puts .symtab, .strtab and .shstrtab
+			 * sections in the end of the output object.
+			 * If the input objects have more sections
+			 * after any of these 3 sections, the section
+			 * table will be reordered. section symbols
+			 * should be regenerated for relocations.
+			 */
+			if (reorder)
+				ecp->flags &= ~SYMTAB_INTACT;
+		} else
+			reorder = 1;
 
 		if (strcmp(name, ".symtab") == 0) {
 			ecp->flags |= SYMTAB_EXIST;